What were his views of race in History???
Do you feel the West is in Decline; and in decline as compared to what???
Well, his conception of 'race' was anti-biological. A race is 'formed' at a certain time and certain place, regardless of biology / ethnicity.
To take an example from history, the Anglo-Saxon peoples displayed their 'race' or 'ethnicity' via burial styles, dress, names, other traditions, etc. There has been a great deal of debate about whether the immigrant Anglo-Saxons completely wiped out the native Britons (the common view in late 19th/early 20th century historiography), or whether Britons did survive in some numbers, but the manner in which they displayed their 'race' is harder to see archaeologically (e.g. in burial rites). Only recently in the history of this subject (from the 90s onwards) have I started to see one or two individuals offering up a different concept of how 'race' was perceived by the early medieval societies, a concept completely other to the distinctly biological one we think of today. The Anglo-Saxon 'race' was 'formed' in England (not in the Continent) during and after the years of settlement (mid C5th-C7th); and the boundaries of 'race' being fluid, potentially allowed Britons to 'become' Anglo-Saxon, which may be an explanation for the British 'archaeological invisibility' other than the idea that a whole people was completely wiped out or forced to flee.
People retroject their own values onto the past. This new understanding seems a massive leap forward for me, and yet such a concept was espoused by Spengler about 90 years ago now. One particular example Spengler himself used was that of the forming of the American 'race'.
But this is just one the many things I found in this work that seems to antedate many modern ideas within the field of history.
The title of the work "The Decline of the West" is, in my opinion, rather a misleading title, and Western decline doesn't really feature in the book until the last few chapters.
I do not "feel" that the West is in decline. But I certainly know it to be in decline as much as I am, and as much as the winter is in decline in order for summer to arrive. Basically, nothing lasts forever. There are a great number of accute observations in this book about current social mores and how they differ to previous ones. I think it is a fallacy that we are ever progressing upward. To me it is not about rise and fall, but merely ebb and flow, or like the hands on a clock. They only rise or fall depending on one's viewpoint, but they are certainly changing for those with an eye patient enough to observe the changes and the signs that herald the changes.